London, England (CNN) -- Hans Blix, the former chief United Nations weapons inspector in Iraq, was testifying Tuesday before Britain's inquiry into the Iraq war.

Blix, the Swedish diplomat who led the effort to find Iraq's suspected nuclear, chemical, and biological weapons programs before the 2003 invasion, has criticized the United States and Britain for launching the war in the absence of evidence.

The United States had discounted Blix's reports that Iraq had no weapons of mass destruction and insisted those programs were simply being concealed. After the invasion, Iraq was found to have dismantled its weapons programs years before.

"I think the U.S. at the time was high on military," Blix told the inquiry. "They felt that they could get away with it (an invasion), and therefore it was decided they would do so."

Blix said he was personally suspicious of Iraq in the build-up to the war, noting, for example, that the country imported uranium. He said he did not mention those suspicions in his official role.

Blix told CNN in 2004 that he began having doubts about the quality of intelligence information from the United States and other countries in January 2003 -- two months before the war -- after his inspectors failed to find any weapons at sites that had been searched based on that information.

Blix said he believed the United States relied too much on Iraqi defectors to provide intelligence on Saddam Hussein's weapons of mass destruction. The defectors were only interested in the liberation of Iraq, he said.

Since the war, Blix has written two books on Iraq and most recently chaired the Weapons of Mass Destruction Commission, which examined how international cooperation could reduce the threat from WMDs.

The Iraq Inquiry, which started last year, is headed by an independent panel led by longtime civil servant John Chilcot.